1. Field of the Invention
This patent relates to liquid dispensing cartridges for automated dispensing systems. More specifically, this patent relates to an ink dispensing cartridge for use with a sheet fed lithographic press.
2. Description of the Related Art
Lithography is a printmaking process dating back to the 1700s in which ink is applied to a plate having both image and nonimage areas. The image areas are ink-receptive and water-repellent. The non-image areas are water-receptive and ink-repellent. In rotary type presses the plate is mounted on a cylinder that rotates during printing. In one typical configuration, the plate cylinder picks up the ink at the image areas and transfers the image to a blanket cylinder which in turn transfers the image to the paper.
In multi-color sheet-fed presses, up to ten inking stations can be placed in series. Each station has its own ink feeding system and handles a separate color. As the paper sheet moves from station to station, a new color is put down at each station.
Because lithographic ink is thixotropic and very viscous, conventional lithographic ink feeding systems require a complex system of drums, vibrators and fountain rollers. In a typical lithographic ink feeding system, workers remove lithographic ink from a drum (or, in some cases, smaller tins) with specially made spatulas and spread the ink across a tray (the ink fountain). Fountain rollers roll against the ink fountain to pick up the ink and transfer it to the plate cylinder. The process is labor intensive and subject to error.
Storing lithographic ink in drums can result in wasted ink if the entire drum is not used because it is difficult to store and reuse ink in drums. The lithographic ink itself is prone to oxidation which can result in color variations from one press run to another, and even from sheet to sheet within a single run. In addition, upon exposure of the ink to the atmosphere, volatile organic compounds (VOCs) evaporate which can cause ink spoilage.
Thus there exists a need for an improved system of storing and dispensing ink for sheet fed lithographic presses. The present invention solves this need by providing an ink cartridge that is easy to fill and ship and can be used with sheet fed lithographic presses of the type that dispense ink from a dispenser mounted over the ink fountain or the fountain roller. During use the ink cartridge moves back and forth across the fountain, dispensing ink into the fountain or directly onto an ink form roller to provide an even consistent layer of ink. In automated presses, the amount of ink in the fountain is continually monitored and replenished as needed.
Numerous cartridge-type dispensers are known in the art, such as those disclosed in Bowe U.S. Pat. No. 3,321,108, MacEwen U.S. Pat. No. 4,373,646 and Nilsson et al. U.S. Pat. No. 5,535,924. However, neither these patents nor any others known to the inventors disclose a cartridge useful for dispensing lithographic ink that can readily be sealed and then reused without wasting a substantial amount of the dispensing material.
Furthermore, conventional cartridge-type dispensers often have built-in protruding nozzles that make it difficult to package, ship and store the cartridges. For example, if the cartridges are shipped in cartons in a vertical position (i.e. standing up), the top of the cartons must be reinforced to prevent the top from collapsing and damaging the cartridge nozzles. If the cartridges are shipped in a horizontal (lying down) position, the sides of the cartons must be suitably reinforced and the cartridges held stationary within the package. The protruding nozzles also prevent stacking of the cartridges either before or after use.
Thus it is an object of the present invention to provide an ink cartridge for easy storing, transporting and dispensing of lithographic ink.
Another object of the present invention is to provide an ink cartridge that can be used in a sheet fed lithographic press to dispense a controlled amount of ink onto an ink fountain.
Still another object of the present invention is to proved an ink dispensing cartridge that minimizes exposure of the ink to the atmosphere.
Yet another object of the present invention is to provide an ink cartridge that can be resealed and reused with the ink remaining stable as to viscosity and color.
Yet another object of the present invention is to provide an ink cartridge which minimizes the amount of residual ink left in the cartridge after use.
Yet another object of the present invention is to provide an ink cartridge having a recessed nozzle for ease of packing, shipping and storing.
Yet another object of the present invention is to provide an ink cartridge having a removably attached nozzle extension for better control of fluid flow.
Yet another object of the present invention is to provide an ink cartridge having a composite body with multiple liner options to meet a user's performance requirements for various inks.
Further and additional objects will appear from the description, accompanying drawings, and appended claims.